title: Novel 3-dimensional motion analysis method for measuring the lumbar spine range of motion: repeatability and reliability compared with an electrogoniometer.
abstract: METHODS
  Repeatability and reliability for measuring methods for real-time lumbar range of motion.
  
  
  OBJECTIVE
  We established a novel set of marker positions for 3-dimensional motion analysis (VICON system) to determine lumbar spine range of motion (LROM) and lumbar motion precisely; we compared the repeatability and reliability of VICON system with those of an electrogoniometer.
  
  
  BACKGROUND
  The assessment of the LROM using x-ray is still one of the most precise methods, despite the radiation exposure. To avoid this, alternative methods, such as the VICON system and electrogoniometer, have been widely used. No study has reported the repeatability and reliability of LROM measurements using a VICON system and electrogoniometer.
  
  
  METHODS
  The VICON system and electrogoniometer measured LROM and lumbar motion in 7 healthy males during 7 days. Differences between both systems were analyzed using Bland-Altman plots. Repeatability and reliability of the LROM measurements was assessed using coefficients of multiple correlations and intraclass correlation coefficients, respectively. Standard error of measurement was calculated to quantify the systematic error in LROM measurements.
  
  
  RESULTS
  The mean maximum LROM values using the VICON system/electrogoniometer were 42°/52° for flexion, 17°/24° for extension, 16°/16° for lateral bending, and 8°/2° for axial rotation, respectively. Between VICON system and the electrogoniometer, Bland-Altman plots revealed no discrepancies in LROM values except for flexion.Coefficients of multiple correlations for LROM showed excellent repeatability. LROM measurements with VICON system showed excellent reliability for flexion and extension and fair-to-good reliability for other motions. LROM measurements with the electrogoniometer showed excellent reliability for flexion and fair-to-good reliability for other motions. Except for axial rotation, maximum intraclass correlation coefficients using VICON system were more reliable than the electrogoniometer for measuring lumbar motion.
  
  
  CONCLUSIONS
  VICON system with our novel marker set allows practical and reliable longitudinal assessment of dynamic LROM.
  
  
  METHODS
  N/A.
authors.affiliation: *Department of Rehabilitation Medicine, The University of Tokyo, Tokyo, Japan †Department of Rehabilitation Medicine, The University of Tokyo Hospital, Japan ‡Department of Sensory-Recognition and Locomotive-Function Sciences in the Super-Aged Society, The University of Tokyo, Tokyo, Japan; and §Department of Medical Engineering, The University of Tokyo Hospital, Tokyo, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Tojima
authors.forename: Naoshi
authors.initials: N
authors.lastname: Ogata
authors.forename: Arito
authors.initials: A
authors.lastname: Yozu
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sumitani
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Haga
mesh_terms: D000328:Adult; D053587:Arthrometry, Articular / Q000379:methods; D001696:Biomechanical Phenomena; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000502:physiology*; D008297:Male; D009038:Motion; D011187:Posture; D011859:Radiography; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012399:Rotation